Physical activity and generalized anxiety disorder: results from The Irish Longitudinal Study on Ageing (TILDA)

Background: Generalized anxiety disorder (GAD) is prevalent and costly. Physical activity (PA) may protect against other mental health disorders, including depression, but its protective effect on GAD remains under-studied in the general population and unstudied among older adults. Therefore, the present study examines associations between meeting World Health Organization PA guidelines (i.e. >= 150 min of moderate PA, >= 75 min of vigorous PA or >= 600MET min of moderate and vigorous PA weekly) and the prevalence of probable GAD and incidence of GAD. Methods: Participants (n = 3950; 56.2% female) aged >= 50 years completed the shortform International Physical Activity Questionnaire and the abbreviated Penn State Worry Questionnaire at baseline and the Composite International Diagnostic Interview - Short Form to clinically assess GAD 2 years later. Prospective analyses included participants without probable GAD at baseline (n = 3236). Results: Prevalence and incidence of GAD were 18.1% (n = 714) and 0.9% (n = 29), respectively. More respondents with GAD were female (72.2% vs 52.7%), aged 50-59 years (51.7% vs 38.7%), had normal waist circumference (52.7% vs 47.8) and smoked (20.4% vs 13.3%; all P < 0.05). Meeting PA guidelines was associated with 25% and 63% lower odds of prevalent [odds ratio (OR) = 0.75, 95% confidence interval: 0.64 to 0.88] and incident (OR = 0.37, 0.17 to 0.85) GAD, respectively, in crude models, and 17% and 57% lower odds of prevalent (OR = 0.83, 0.70 to 0.98) and incident (OR = 0.43, 0.19 to 0.99) GAD,respectively, following adjustment for age, sex, waist circumference, social class and smoking. Conclusions: In addition to established physical health benefits of PA, the present findings support the importance of increasing PA at the population-level for mental health.